June 2023
Volume 64, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2023
Automated method to determine Centration/Registration for Refractive Corneal Lenticule Extraction Treatments
Author Affiliations & Notes
  • Samuel Arba Mosquera
    Research & Development, SCHWIND eye-tech-solutions GmbH, Kleinostheim, Bavaria, Germany
  • Victor Derhartunian
    Eye + Laser, Austria
  • Hamed Haidari
    Research & Development, SCHWIND eye-tech-solutions GmbH, Kleinostheim, Bavaria, Germany
  • Thomas Magnago
    Research & Development, SCHWIND eye-tech-solutions GmbH, Kleinostheim, Bavaria, Germany
  • Maren-Christina Blum
    Research & Development, SCHWIND eye-tech-solutions GmbH, Kleinostheim, Bavaria, Germany
  • Footnotes
    Commercial Relationships   Samuel Arba Mosquera SCHWIND eye-tech-solutions, Code E (Employment), SCHWIND eye-tech-solutions, Code P (Patent); Victor Derhartunian None; Hamed Haidari None; Thomas Magnago SCHWIND eye-tech-solutions, Code E (Employment), SCHWIND eye-tech-solutions, Code I (Personal Financial Interest), SCHWIND eye-tech-solutions, Code P (Patent); Maren-Christina Blum SCHWIND eye-tech-solutions, Code E (Employment)
  • Footnotes
    Support  None
Investigative Ophthalmology & Visual Science June 2023, Vol.64, 5327. doi:
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    • Get Citation

      Samuel Arba Mosquera, Victor Derhartunian, Hamed Haidari, Thomas Magnago, Maren-Christina Blum; Automated method to determine Centration/Registration for Refractive Corneal Lenticule Extraction Treatments. Invest. Ophthalmol. Vis. Sci. 2023;64(8):5327.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : To evaluate the performance of auto-centration for corneal lenticule extraction treatment on a new commercial femtosecond laser system.

Methods : Preoperative and 3-month postoperative tomographies from 48 eyes (30 patients) who underwent lenticule corneal shaping (LeCS) with a new commercial femtosecond laser system were collected. During patient docking to the laser system, a camera provides the operator with a coaxial view through the patient interface, including a static overlay of the target pupil position. The operator is instructed to bring the pupil (detected by a video-based Eye-Tracker) coincident with the target pupil position (within 200µm). Suction is applied, and it is confirmed that the pupil remains within the target hot zone, or at least within the maximum permissible zone (700µm); otherwise, a new docking is attempted. The last valid laser videoframe of the eye-tracker is used for cyclotorsion control, and the torsional misalignment from the diagnostic image is determined and accounted for. The centre of mass of the central 9-mm diameter disc of the pre- to post-operative differences has been calculated (automatically, without human supervision) and it has been considered as an unbiased estimate of the centration. Its difference to the aimed centration determines the decentration.

Results : The centration/registration process was successful in all 48 eyes. From the differences in corneal thickness, on average, treatments were decentred by 130±76µm (up to 375µm) from the corneal vertex (proxy for the visual axis). From the differences in total corneal refractive power, on average, treatments were decentred by 270±111µm (up to 718µm) from the corneal vertex. 23% and 79% of the treatments were decentred by less than 200µm, from the differences in total corneal refractive power and corneal thickness, respectively. From manifest refraction, 55% and 90% of the treatments were within 5 degree and 15 degree from the aimed astigmatic axis, respectively.

Conclusions : Automated Centration/Registration for Refractive Corneal Lenticule Extraction Treatments improves the accuracy of treatment centration and torsion, leading to residual decentrations and torsions at least as good as (or better than) with previous methods. The automated method for determination of the centre of the OZ (unbiased estimate of the centration) can be applied to any topographic or tomographic map.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.

 

 

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